This invention relates to stacked projectile launchers in general. Specifically, the invention includes a barrel insert, a barrel assembly, a method of firing axially stacked projectiles, a method of configuring a stacked projectile launcher, and a stacked projectile launcher.
Reference in this specification to any prior publication (or information derived from it), or to any matter which is known, is not, and should not be taken as an acknowledgment or admission or any form of suggestion that the prior publication (or information derived from it) or known matter forms part of the common general knowledge in the field of endeavour to which this specification relates.
The current Applicant has developed a number of stacked projectile launcher systems. Certain applications of these types of stacked projectile launcher systems require that projectiles fired from a single barrel have substantially similar muzzle velocities.
For example, airburst grenades or similar projectiles can be fired from these stacked projectile weapons. In these applications, it becomes important that each projectile leaves a barrel of the weapon at similar muzzle velocities as such projectiles can have fuses or timing circuitry for arming or detonating a payload of the projectile after a certain amount of time has elapsed after the projectile has been fired. If the stacked projectiles have different muzzle velocities when fired, it can become difficult to configure proper arming or detonation timing. This difficulty similarly applies to launching of stacked fireworks.
Another application includes less than lethal projectiles which are required to leave the barrel with consistent predetermined muzzle velocities such that the desired terminal effect can be achieved.
Range and trajectory are in part determined by muzzle velocity, particularly with low muzzle velocity applications. But even with low muzzle velocity applications, up to 400 m/s, the pressures generated within the barrel can be very high to extreme, e.g. reaching pressures in the 10 s of MPa to 100 s of MPa depending on the mass of the projectile. This makes consistent muzzle velocities difficult to achieve, particularly for travelling charge projectiles and particularly where the same weapon is to fire a variety of projectiles with, for example, varying masses.
Furthermore, achieving consistent muzzle velocity in stacked projectile launchers is particularly difficult to achieve in applications where the projectiles are loaded into the launcher by hand. The friction between the projectile and barrel wall must be sufficiently low for the projectile to be inserted manually, i.e. a loose fit, whilst at the same time allowing sufficient friction between the barrel wall and projectile to allow for pressure generated sealing between the barrel wall and projectile when the projectile is fired.